What Are Bacteriophages?


Bacteriophages are one of the many types of viruses, which are the most simple living things. When viruses infect animals, plants, or humans, they are called eukaryotic viruses, and they are called bacteriophages when they infect bacteria.

All viruses are very tiny microorganisms that can only be observed with a huge magnification by using a special microscope. Bacteriophages are very abundant; actually, there are thousands of millions of bacteriophages around us, although we cannot see them.

They live everywhere: in the soil, in the oceans, in our bodies, and also in food (we eat bacteria and bacteriophages every day).

But we should not worry about bacteriophages because they are harmless to all of us and also to animals and plants. Bacteriophages are only dangerous for bacteria because they need bacteria to reproduce.

Bacteriophages Reproduction

The reproduction of bacteriophages is quite different from that of animals or plants. Their reproductive process, called the lytic cycle, happens very quickly; for some bacteriophages, it only takes 30 min!

If we were able to stop the process and see what is happening inside the cell, we would observe three different steps (See image above). At the end of the lytic cycle, the bacterium dies. Bacteriophages are, therefore, the natural enemies of bacteria.

In nature, both bacteria and bacteriophages are necessary to keep microscopic ecosystems working properly. This is similar to what occurs with animals, when the predator (fox) and the prey (hare) live together in the same place, despite being enemies.

Are Bacteriophages Useful?

Yes, they are. We can use bacteriophages to kill bad bacteria in a way that is similar to the way we use antibiotics.

Moreover, bacteriophages have some advantages compared with antibiotics. For instance, antibiotics usually kill different types (species) of bacteria, while bacteriophages generally attack only one kind of bacteria.

As a result, bacteriophages that kill bad bacteria do not affect beneficial bacteria, and most of the time we do not want to exterminate all the bacteria, only the “bad guys.” Of course, before we can give people bacteriophages as medicines, the bacteriophages need to be studied to be sure that they are totally safe.

Actually, a great number of scientists working on this research area have found other uses for bacteriophages. For example, bacteriophages can be used to clean hospitals or industrial surfaces, since they can destroy undesirable bacteria like disinfectants do.

It is also possible include bacteriophages in foods, which will work similar to chemical preservatives. Bacteriophages will wait in the food until some bad bacteria contaminate it and, like playing hide-and-seek, when the bacteriophages find their bacterial targets, they will catch them.

Gutiérrez D, Fernández L, Martínez B, Rodríguez A and García P (2016)
Bacteriophages: The Enemies of Bad Bacteria Are Our Friends!
Front Young Minds. 4:30. doi: 10.3389/frym.2016.00030

Authors: Gutiérrez D, Fernández L, Martínez B, Rodríguez A and García P.
Published under Creative Commons Attribution License (CC BY), with portions omitted for length